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March Cover

The photo on the March-cover 2018, shows some of the 163 species of seeds that was used to test the trade-off between physical and chemical defenses, in the paper "Tradeoff between physical and chemical defense in plant seeds is mediated by seed mass", by Bo Wang et al. .

"Trade-off is one of the fundamental ecological questions and has been drawing constant attentions by a wide range of researchers. It is intuitive that a trade-off should exist between physical and chemical defences in organs because of finite defence resources, yet many studies have failed to detect this trade-off. We studied the trade-off between physical and chemical defences in plant seeds of 163 common species in Xishuangbanna tropical forest, Southwest China. Our analyses accounted for phylogenetic signal in trait correlations, allowing us to identify the trait correlations that existed independently of common ancestry.

We hypothesize that trade-off between physical and chemical defences is mediated by the total resource allocation to individual organs. We show that the trade-off between physical and chemical defences declines with increasing seed mass, such that the correlation between physical and chemical defences is more negative among species with small seeds and less negative or even positive among species with large seeds.

Our findings help to understand the mechanism of trade-off between physical and chemical defences. Our study also suggests that total resource acquisition should be considered when evaluating defence trade-offs. However, as it is usually difficult to measure this resource acquisition variation, thus we should utilize easily measured proxies of acquisition variation to quantify trade-offs.

The result shows that trade-offs cannot easily be evaluated in isolation. Third-party factors affect trade-offs. If we are to advance our understanding of trade-offs, we need to be much more congnizant of context and other parameters affecting the trade-offs."

Oikos Journal

Oikos is a journal issued by the Nordic Ecological Society and is one of the leading peer-reviewed journals in ecology. Oikos publishes original and innovative research on all aspects of ecology, defined as organism-environment interactions.